A wide variety of communications alternatives are currently available to telecommunications users. For example, facsimile transmission of printed matter is available through what is commonly referred to as a stand-alone fax machine. Alternatively, fax-modem communication systems are currently available for personal computer users which combine the operation of a facsimile machine with the word processor of a computer to transmit documents held on computer disk. Modem communication over telephone lines in combination with a personal computer is also known in the art where file transfers can be accomplished from one computer to another. Also, simultaneous voice and modem data transmitted over the same telephone line has been accomplished in several ways.
Modem technology has recently multiplexed the transmission of various nonstandard data with standard digital data, such as voice over data communications, creating a hybrid datastream of standard and nonstandard data. Accepted negotiation methods may be employed to negotiate parameters for the standard data transfer, however, the additional multiplexing of nonstandard data into the datastream creates problems in negotiating consistent data parameters for the nonstandard data transfer. Furthermore, improvements in the hardware and software used to tranmit and receive the hybrid datastream have generated a variety of options for nonstandard data transfer. For example, in voice over data transmissions, the nonstandard communication parameters which must be negotiated include parameters specifying the speech compression algorithm and speech compression ratio used in the voice data transfer.
Present modem negotiation methods employ escape sequences for communications parameter negotiation, and may result in interruption of the data transfer if a protocol must be renegotiated.
Therefore, there is a need in the art for a means for negotiating nonstandard data transmission parameters which does not rely on the use of escape sequences to negotiate the data parameters.
There is also a need in the art for a method of negotiating data transmission parameters during the data transmission, without interruption of the transmission or the use of escape sequences.